REGULATION OF FLORAL MERISTEMS AND FLORAL ORGANS IN ARABIDOPSIS

Abstract

DURING THE LIFE CYCLE OF PLANTS, THE REPRODUCTIVE STAGE IS ONE OF THE MOST COMPLICATED PROCESSES, WHICH PLAYS A KEY ROLE IN REPRODUCTION AND CROP YIELD. APPROPRIATE DEVELOPMENT OF REPRODUCTIVE ORGANS REQUIRES PRECISE SPATIOTEMPORAL REGULATION OF MULTIPLE GENES. INITIATION OF THE CARPEL PRIMORDIA IS MARKED BY THE TERMINATION OF FLORAL STEM CELLS. ALTHOUGH GENETIC EVIDENCES HAVE SUGGESTED THAT THE YABBY GENE CRABS CLAW (CRC) REGULATES THE DEVELOPMENT OF CARPELS, AS WELL AS THE FLORAL MERISTEM DETERMINACY AS A TARGET OF THE HOMEOTIC PROTEIN AGAMOUS, THE UNDERLYING MECHANISM REMAINS UNCLEAR. HERE WE SHOW THAT THE TETRASPANIN-ENCODING GENE TONADO2 (TRN2) AND THE AUXIN BIOSYNTHESIS GENE YUCCA4 (YUC4) ACT AS DOWNSTREAM TARGETS OF CRC. WE ILLUSTRATE THAT CRC REPRESSES TRN2 AND ACTIVATES YUC4. THESE TWO PATHWAYS TOGETHER CONTRIBUTE TO THE ESTABLISHMENT OF AUXIN DISTRIBUTION IN CARPELS, WHICH ACCOUNTS FOR THE DEVELOPMENT OF STYLE AND CARPEL FUSION, AS WELL AS THE FLORAL STEM CELL TERMINATION. TH